Construction jobs, such as the building or repair of foundations, facings, etc., often require the use of large amounts of structural grout. One example of such a job is the reinforcing of hollow concrete block walls, as described in U.S. Pat. No. 6,655,107, dated Dec. 2, 2003.
These types of jobs are generally done over a period of time, with the need for prepared grout being everywhere from virtually continuous to often interrupted over the duration of the job. For these jobs, the grout must be available when needed, so that the workers are not waiting for grout, but also such that the grout is not sitting so long as to set prior to use.
Preparation of structural grout at the job site requires having the components for making the grout available at the site for workers to mix. These components are well known in the art and generally include a Portland cement, an aggregate such as sand and water. When mixed at a job site, the grout is generally prepared in batches of about one-half cubic yard each, based on the prepackaged nature of Portland cement generally used that comes in bags of about 94 pounds.
Although such batches can be mixed individually in tubs or mixers, they must then be used quickly after mixing stops to avoid setting prior to use. To accomplish this, a batch of structural grout that has been prepared but cannot be used quickly must be continuously mixed so that it will not set. On the other hand, to ensure that workers are not standing idle waiting for more prepared grout to continue a job, another batch must always be prepared and ready for use.
Based on these requirements, efforts have been made to prepare grout more efficiently at the job site. These have included grout stations comprising a mixer for mixing the grout components, a hopper with an auger or agitator for maintaining the mixed grout in a usable state, a motor to run the mixer and agitator and a pump to move the grout to the location where it is being used. Several examples of such grout stations with the components mounted on a skid for mobility are CHEMGROUT® models CG-500, CG-600 and CG-680.
Other mobile plants used for mixing concrete or other such materials comprised of components mixed at a job site have been described for use at the site. Examples include U.S. Pat. No. 4,071,226, directed to a transporting vehicle having separate hoppers for the components to be mixed that discharge to a conveying and mixing trough; U.S. Pat. No. 5,785,420, directed to a trailer having a hopper divided into compartments for the components and a conveyer to convey the components to a mixer; U.S. Pat. No. 4,907,890, directed to a portable mixing device with an upper frame for a hopper which drops dry ingredients onto a conveyer which deposits the ingredients into a mixer where water is introduced; and U.S. Pat. No. 4,506,982, directed to a trailer for continuously blending a viscous liquid having hydraulically driven pumps and motors to feed the viscous liquid and solids to a blending chamber.
However, the prior art does not provide a mobile device that meets the demands encountered when a supply of grout is required on an as needed basis. In this regard, there is a need for a device that can provide grout at a job site on an as needed basis, which can be easily and efficiently operated by a limited number of workers.